Implementing 3-Switch XOR Ladder Logic with Internal Bit
Implement a 3-SPST switch XOR light circuit in LogixPro or RSLogix 500 using an internal relay bit. Includes truth tables, boolean equations, and verified.
Tasked with executing high-speed control logic and system coordination, the Mitsubishi Electric FX5U-64MR/DS functions as a core processing unit within the MELSEC iQ-F series platform. This controller integrates processing power, integrated communication interfaces, and localized high-density I/O handling on a single compact chassis. Equipped with 64 built-in physical I/O points, the unit utilizes a 24V DC power supply to run its internal CPU architecture and supply auxiliary power to localized extension modules. The robust screw terminal block interface ensures dependable, vibration-resistant terminations in challenging industrial operating environments.
| Parameter | Value / Specification |
|---|---|
| Manufacturer | Mitsubishi Electric |
| Model Number | FX5U-64MR/DS |
| Series Name | MELSEC iQ-F Series |
| Input Power Supply | 24 V DC (+20%, -15%) |
| Total Built-In I/O Points | 64 Points |
| Digital Input Specifications | 32 Points, 24 V DC (Sink type) |
| Digital Output Specifications | 32 Points, Relay outputs |
| 5 V DC Internal Supply Capacity | 1100 mA |
| 24 V DC Internal Supply Capacity | 740 mA |
| Termination Interface | Screw terminal block |
| Shipping Weight (Calculated) | 2.0 kg |
| Terminal / Port | Functional Assignment / Description |
|---|---|
| L+ / M | Main DC power supply input terminals (24 V DC) |
| Functional Ground (FG) | System noise filtration and grounding reference point |
| X0 to X37 | 24 V DC Sink digital input terminals |
| Y0 to Y37 | Mechanical relay switching contact output terminals |
Migrating old architectures from FX3U to the FX5U platform requires standard program migration through GX Works3 software. Be aware that the FX5U-64MR/DS is a 24 V DC input model; do not substitute or confuse this model code with the AC line-powered alternative (FX5U-64MR/ES), as their wiring schemas and internal grounding configurations differ significantly.
To protect the mechanical relay contacts in the FX5U-64MR/DS when driving inductive loads like solenoids or contactors, you must install external surge-suppression devices. Use an RC snubber network across AC inductive loads, and a freewheeling diode across DC inductive loads to prevent premature point-welding of internal relays.
When routing communication cables and wiring the DC inputs, ensure that all logic signals are physically isolated from high-voltage motor conductors. Use class-D grounding (100 ohms or less) dedicated solely to the PLC system to minimize electromagnetic interference on the internal CPU bus and high-speed counter registers.
Mount the CPU module securely on a standard 35mm DIN rail or utilize direct screw mounting in an enclosed, low-vibration control panel environment.
Connect the dedicated functional ground (FG) terminal to the common protective ground busbar before finishing auxiliary wiring.
Wire the 24V DC supply cables directly to the L+ and M terminals, verifying correct polarity with a standard digital multimeter prior to initial system power-up.
Global Express Shipping
Returns & Warranty

Tasked with executing high-speed control logic and system coordination, the Mitsubishi Electric FX5U-64MR/DS functions as a core processing unit within the MELSEC iQ-F series platform. This controller integrates processing power, integrated communication interfaces, and localized high-density I/O handling on a single compact chassis. Equipped with 64 built-in physical I/O points, the unit utilizes a 24V DC power supply to run its internal CPU architecture and supply auxiliary power to localized extension modules. The robust screw terminal block interface ensures dependable, vibration-resistant terminations in challenging industrial operating environments.
| Parameter | Value / Specification |
|---|---|
| Manufacturer | Mitsubishi Electric |
| Model Number | FX5U-64MR/DS |
| Series Name | MELSEC iQ-F Series |
| Input Power Supply | 24 V DC (+20%, -15%) |
| Total Built-In I/O Points | 64 Points |
| Digital Input Specifications | 32 Points, 24 V DC (Sink type) |
| Digital Output Specifications | 32 Points, Relay outputs |
| 5 V DC Internal Supply Capacity | 1100 mA |
| 24 V DC Internal Supply Capacity | 740 mA |
| Termination Interface | Screw terminal block |
| Shipping Weight (Calculated) | 2.0 kg |
| Terminal / Port | Functional Assignment / Description |
|---|---|
| L+ / M | Main DC power supply input terminals (24 V DC) |
| Functional Ground (FG) | System noise filtration and grounding reference point |
| X0 to X37 | 24 V DC Sink digital input terminals |
| Y0 to Y37 | Mechanical relay switching contact output terminals |
Migrating old architectures from FX3U to the FX5U platform requires standard program migration through GX Works3 software. Be aware that the FX5U-64MR/DS is a 24 V DC input model; do not substitute or confuse this model code with the AC line-powered alternative (FX5U-64MR/ES), as their wiring schemas and internal grounding configurations differ significantly.
To protect the mechanical relay contacts in the FX5U-64MR/DS when driving inductive loads like solenoids or contactors, you must install external surge-suppression devices. Use an RC snubber network across AC inductive loads, and a freewheeling diode across DC inductive loads to prevent premature point-welding of internal relays.
When routing communication cables and wiring the DC inputs, ensure that all logic signals are physically isolated from high-voltage motor conductors. Use class-D grounding (100 ohms or less) dedicated solely to the PLC system to minimize electromagnetic interference on the internal CPU bus and high-speed counter registers.
Mount the CPU module securely on a standard 35mm DIN rail or utilize direct screw mounting in an enclosed, low-vibration control panel environment.
Connect the dedicated functional ground (FG) terminal to the common protective ground busbar before finishing auxiliary wiring.
Wire the 24V DC supply cables directly to the L+ and M terminals, verifying correct polarity with a standard digital multimeter prior to initial system power-up.
Global Express Shipping
Returns & Warranty
Orders are processed and delivered Monday-Friday (excluding public holidays).
For full eligibility, restocking fees, and international return details, please view our official Refund & Return Policy .
| Country of origin |
United States
|